US club class definition

On Monday, February 27, 2017 at 6:02:51 PM UTC-5, Steve Leonard wrote:
On Monday, February 27, 2017 at 3:12:39 PM UTC-6, wrote:
Beginner's Question for UH or other recognized experts...

Is the handicap for either club class or sports class just based on a glider's "Best L/D" at a given wing loading (I assume max theoretical wing loading) or does it also take into account how straight or curved a glider's polar is? What effect does wing loading have on the handicap, if any?

/Chris Schrader (B2G)

Non expert, unrecognizable opinion. Handicaps are based more on the polar curve for a sailplane without ballast, and a set of assumed conditions. It is a measure of the cross country achievable speed with a given type of task, wind, and thermal strength. There were many assumptions made in determining actual achievable climb rate based on vertical motion of the air in which the plane will climb. Glide polars for calculation have been anything from factory provided, to those measured by the Idaflieg, Dick Johnson, Paul Bikle, and others.

A specific sailplane type was set as the "Standard" and assigned a handicap of 1.0. In the US, higher performance (higher achievable cross country speed in the assumed conditions) gives a lower handicap number. The handicap is, under the defined conditions, to correct the achieved speed of any plane with the same pilot to have the same handicapped speed on the same day.. In other words, the handicap is attempting to make all planes equal, and let the best pilot win.

The basic handicaps have been adjusted in numerous ways over the years. I had heard that Carl had used contest results to fine tune things. There have been attempts to adjust the basic handicap for different locations with stronger or weaker lift than the initial assumed lift, more or less wind, etc.

As to wing loading, the same plane at a higher wing loading will have a lower handicap number. This goes back to the assumptions, and they lead you to the conclusion that if you are able to climb at the assumed rate, a heavier model of the same plane will achieve a higher cross country speed. So, it should have a lower handicap number, because in the US system, achieved speed is multiplied by the HC to determine "handicapped speed".

In the US, there are now adjustments made to the handicap if the plane and pilot is either above or below the reference weight. So, a plane and pilot that is over the reference weight will have its handicap number reduced, and if the plane and pilot is below the reference weight, its handicap number will be increased.

That is my understanding of the current system in the US as it stands today. The same handicap number defined for "Sports Class" is used if a plane is flown in "Club Class". It is just that "Club Class" only permits planes of a certain span (or less) and a certain handicap range to participate. "Sports Class" lets anyone compete.

Hope this helps.

Steve Leonard

This is a good synopsis of how the handicapping system works.
UH